4,950 research outputs found

    The Non-Relativistic Evolution of GRBs 980703 and 970508: Beaming-Independent Calorimetry

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    We use the Sedov-Taylor self-similar solution to model the radio emission from the gamma-ray bursts (GRBs) 980703 and 970508, when the blastwave has decelerated to non-relativistic velocities. This approach allows us to infer the energy independent of jet collimation. We find that for GRB 980703 the kinetic energy at the time of the transition to non-relativistic evolution, t_NR ~ 40 d, is E_ST ~ (1-6)e51 erg. For GRB 970508 we find E_ST ~ 3e51 erg at t_NR ~ 100 d, nearly an order of magnitude higher than the energy derived in Frail, Waxman and Kulkarni (2000). This is due primarily to revised cosmological parameters and partly to the maximum likelihood fit we use here. Taking into account radiative losses prior to t_NR, the inferred energies agree well with those derived from the early, relativistic evolution of the afterglow. Thus, the analysis presented here provides a robust, geometry-independent confirmation that the energy scale of cosmological GRBs is about 5e51 erg, and additionally shows that the central engine in these two bursts did not produce a significant amount of energy in mildly relativistic ejecta at late time. Furthermore, a comparison to the prompt energy release reveals a wide dispersion in the gamma-ray efficiency, strengthening our growing understanding that E_gamma is a not a reliable proxy for the total energy.Comment: Submitted to ApJ; 13 pages, 6 figures, 1 table; high-resolution figures can be found at: http://www.astro.caltech.edu/~ejb/NR

    ROLE OF PLACEBO AND PSYCHOLOGICAL COUNSELING IN THE MANAGEMENT OF SHUKRAGAT VATA W.S.R. TO PREMATURE EJACULATION

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    Premature Ejaculation is very common male sexual disorder. Anxiety, Stress, Fear etc. are the main etiological factor of premature ejaculation. In Ayurveda, this condition can be correlated with Shukragat Vata. In this clinical trial management is done by Placebo with psychological counseling. Placebo (starch powder) is given 6 gm. two times a day with Koshna jal (warm water) as a Anupana in 20 patients. Placebo with psychological counseling was found to be effective to a certain extent in the management of Shukragat Vata (premature ejaculation). This study was conducted on 23 patients with statistically highly significant result (p<0.001) on the chief complaints of Premature Ejaculation

    Investigation of laser ablated ZnO thin films grown with Zn metal target: a structural study

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    High quality ZnO thin films were gown using the pulsed laser deposition technique on (0001) Al2_2O3_3 substrates in an oxidizing atmosphere, using a Zn metallic target. We varied the growth conditions such as the deposition temperature and the oxygen pressure. First, using a battery of techniques such as x-rays diffraction, Rutherford Backscattering spectroscopy and atomic force microscopy, we evaluated the structural quality, the stress and the degree of epitaxy of the films. Second, the relations between the deposition conditions and the structural properties, that are directly related to the nature of the thin films, are discussed qualitatively. Finally, a number of issues on how to get good-quality ZnO films are addressed.Comment: To be published in Jour. Appl. Phys. (15 August 2004

    Simulations of Oligomeric Intermediates in Prion Diseases

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    We extend our previous stochastic cellular automata based model for areal aggregation of prion proteins on neuronal surfaces. The new anisotropic model allow us to simulate both strong beta-sheet and weaker attachment bonds between proteins. Constraining binding directions allows us to generate aggregate structures with the hexagonal lattice symmetry found in recently observed in vitro experiments. We argue that these constraints on rules may correspond to underlying steric constraints on the aggregation process. We find that monomer dominated growth of the areal aggregate is too slow to account for some observed doubling time-to-incubation time ratios inferred from data, and so consider aggregation dominated by relatively stable but non-infectious oligomeric intermediates. We compare a kinetic theory analysis of oligomeric aggregation to spatially explicit simulations of the process. We find that with suitable rules for misfolding of oligomers, possibly due to water exclusion by the surrounding aggregate, the resulting oligomeric aggregation model maps onto our previous monomer aggregation model. Therefore it can produce some of the same attractive features for the description of prion incubation time data. We propose experiments to test the oligomeric aggregation model.Comment: 8 pages, 10 figures For larger versions of several figures, see http://asaph.ucdavis.edu/~dmobley and click on the prion paper lin

    Influence of catalyst deactivation on the nature of the steady state solutions for reactions on catalytic surfaces

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    Evidence for a quantum phase transition in the electron-doped cuprate Pr2-xCexCuO4+d from Hall and resistivity measurements

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    The doping and temperature dependence of the Hall coefficient, RH, and ab-plane resistivity in the normal state down to 350mK is reported for oriented films of the electron-doped high-Tc superconductor Pr2-xCexCuO4+d. The doping dependence of b (r=r0+AT^b) and R_sub_H (at 350 mK) suggest a quantum phase transition at a critical doping near x=0.165.Comment: 11 pages 4 figures Phys. Rev. Lett. 92, 167001 (2004

    A 450-day light curve of the radio afterglow of GRB 970508: Fireball calorimetry

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    We report on the results of an extensive monitoring campaign of the radio afterglow of GRB 970508, lasting 450 days after the burst. The spectral and temporal radio behavior indicate that the fireball has undergone a transition to sub-relativistic expansion at t~100 days. This allows us to perform "calorimetry" of the explosion. The derived total energy, ~5\times 10^{50} erg, is well below the ~5\times 10^{51} erg inferred under the assumption of spherical symmetry from gamma-ray and early afterglow observations. A natural consequence of this result, which can also account for deviations at t<100 days from the spherical relativistic fireball model predictions, is that the fireball was initially a wide-angle jet of opening angle ~30 degrees. Our analysis also allows to determine the energy fractions carried by electrons and magnetic field, and the density of ambient medium surrounding the fireball. We find that during the sub-relativistic expansion electrons and magnetic field are close to equipartition, and that the density of the ambient medium is ~1/cm^3. The inferred density rules out the possibility that the fireball expands into a strongly non-uniform medium, as would be expected, e.g., in the case of a massive star progenitor.Comment: 33 pages, including 7 figures, submitted to Ap

    Collective behavior of stock price movements in an emerging market

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    To investigate the universality of the structure of interactions in different markets, we analyze the cross-correlation matrix C of stock price fluctuations in the National Stock Exchange (NSE) of India. We find that this emerging market exhibits strong correlations in the movement of stock prices compared to developed markets, such as the New York Stock Exchange (NYSE). This is shown to be due to the dominant influence of a common market mode on the stock prices. By comparison, interactions between related stocks, e.g., those belonging to the same business sector, are much weaker. This lack of distinct sector identity in emerging markets is explicitly shown by reconstructing the network of mutually interacting stocks. Spectral analysis of C for NSE reveals that, the few largest eigenvalues deviate from the bulk of the spectrum predicted by random matrix theory, but they are far fewer in number compared to, e.g., NYSE. We show this to be due to the relative weakness of intra-sector interactions between stocks, compared to the market mode, by modeling stock price dynamics with a two-factor model. Our results suggest that the emergence of an internal structure comprising multiple groups of strongly coupled components is a signature of market development.Comment: 10 pages, 10 figure

    EFFICACY OF SHIVA GUTIKA WITH SARASWATARISHTA IN THE MANAGEMENT OF AGE ASSOCIATED MILD COGNITIVE IMPAIRMENT (AAMCI)

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    Objective: To find the efficacy of Shiva gutika with Saraswatarishta in management of Age Associated Mild Cognitive Impairment (AAMCI). To review the literature of mild cognitive impairment, Jara, and aging as per modern science and Ayurveda. To observe side effects of the drug if any. To access effect of drug on other signs and symptoms of Jara.Method: Open Trial study was conducted on 25 patients having AAMCI and were selected for the study randomly. The patients received 1gm Shiva gutika once a day with 40ml Saraswatarista as Anupan for 3 months.Assessment Criteria: Improvement in all the six cerebral higher functions on the basis of various tests such as MMSE, CAMCOG (CAMDEX), ADL/IADL, GDS.Follow up: 0, 15th, 30th, 45th, 60th, 75th, 90th day.Duration: Total duration study was 90 Days. This study was carried out in Bharati Vidyapeeth Deemed University College of Ayurved &amp; Hospital Pune in Year 2010 and 2011.Results: Comparing all the symptoms before and after treatment had significant action in age associated mild cognitive impairment (AAMCI). No side effects of the drug during clinical trial were seen.Statistical Analysis: The Statistical Analysis reveals that Shiva gutika with Saraswatarista as Anupan effective in age associated mild cognitive impairment (AAMCI).Conclusion: Shiva gutika with Saraswatarista shared significant results in AAMCI. The overall effect of drug on ADL &amp; IADL showed significant result
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